[IMtheNRA]

Hello, I've seen several references to "chamfering charge holes" on some gunsmithing sites and I was wondering what is the benefit of this work.

[Mad Magyar]

Makes it easier to load, especially by a speedloader....On my 9mm revolver, I wish it would have been chamfered since it is an extreme tight fit....

[The Lone Haranguer]

Yes, it is to make reloading slightly easier. It only works on revolvers whose cylinders and extractor stars are not rebated to shroud the case rim, which is most of them these days. You only lightly "break" the sharp edge - just enough so the bullet nose doesn't catch on it - or there will be too little support for the rim. Another thing that makes the reloading process easier is bullets with rounded profiles. Wadcutters, semi-wadcutters or any bullet with a sharp shoulder don't lend themselves to speedloading.

[.38 Special]

It only works on revolvers whose cylinders and extractor stars are not rebated to shroud the case rim...
If I'm reading that correctly, it isn't quite right. I have several old S&Ws with rebated cylinders and they've all been chamfered. Granted, the rebated cylinders limits the depth of the chamfer, but as you pointed out, the idea is to "break" the sharp edges, not create funnels.